Process of treating wood for storage-battery separators.



. saarns Parana orauoa.

ware as. smart, or cameraman. rruusrweula essmuon T0 murmurrm s'rosaes BATTERY cerium. or. PHILADELPHIA, rsnusrn ama a or- EQMTION OF PENN$YLVANIA- rnoonss or TREATING woo FOB STORAGE-BATTERY sErARA'roRs.

Kc Drawing.

To all whom it may concern Be it known that 1, JAMES M. Snmuun, of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Improvement in Processes or" Treating Wood for Storage -Battery Separators, whereof the following is a specification.

.It is the object of my invention to pro-- vide wooden diaphragms to be used as separators between the positive and negative plates of a secondary or storage battery, de-. prived of the natural constituents of the wood which, if allowed to remain, tend to decompose when immersed in the usual electrolyte, viz., an aqueous solution of sulfnric acid, and subjected to. the action of the battery, and form acetic acid or other products which are deleterious to the battery. Such deleterious constituents of the natural wood are principally contained in its ligrione; the formation of acetic acid and other acids of like nature being a characteristic of such decomposition of lignone. For instance, acetic acid may be formed from the wood by simple hydrolysis of lignocellulose, and oxidation of wood neuclei. of ketonic or aldehydic structure.

It is characteristic of my invention that the wood is deprived of said deleterious constituents by salts, and that the wood treated therewith may be allowed to dry in the interim between its treatment and its inclusion in a battery, without materially shrinking, warping, or cracking.

Moreover, my invention is advantageous in that separators treated in accordance therewith have greater strength and durability than wood separators treated with the ordinary acid or alkaline processes.

The wood to be'trcated is cut in suitable forms, approximately plane sheets, and immersed in an aqueous solution of a salt of hydrogen sulfid; for example, sodium sulfid or potassium sulfid. For instance, I have used aqueous solutions of sodium sulfid containing from 2 to 20 per cent. of said salt, and at temperatures from 15 to 100 degrees centigrade. However, I do not wish to limit myself to said percentages or temperatures.

The sulfid solution acts by reason of its mild hydrolyzing eliect upon the wood, by combination of the metal of the sulfid with the wood acids, such as acetic acid and other" Specification of Letters Eatent. Application me December as, 1912. Serial'No. 738,592,

Patented May 26, 1914..

acids of that series, which are harmflul to lead battery plates, and also by reason of its reducingefi'ect. The reducing effects of the sulfid tend to insure complete treatment of the wood by preventing reversal of the process and oxidation of the products.

My improved process is particularly advantageous, as distinguished from other processes of the prior art, in that it produces a strong, durable separator in a very short time. For instance, using a 15 per cent. solution of sodium sulfid at 100 degrees centigrade, a complete treatment may be effected in one hour; the product thereof being Ill6- chanically strong andallording long life in a storage battery. In this connection it may he observed that the acid and alkaline processes of the prior art require twcnty-four hours at less cost than heretofore but requires correspondingly less floor space and treating apparatus.

It may be observed that the sulfid solution is selective in its action in that it extracts from the wood the constituents thereof harmtul to a battery, without detrimental attack upon the wood structure.

The wood separators treated as above con-- templated may he washed, to free them of said products which are soluble in water, and then dried with. or without artificial heat,'and with or without pressure. Good results are obtained by laying the separators horizontally in piles, with a weight on top of each pile. I

I do not desire to limit myself to the particular. salts named or to the precise proportions thereof above stated, or to the particular temperatures named, as various modifications may be made therein without departing from the essential features of my invention as defined in the appended claims.

1. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous SOllltlOIl of sodium sulfid while maintaining said solution at a temperature of from 15 to 100 degrees centigrade; washing from the treated wood the products of decomposition efi'ected by the action of said solution; and, drying the Wood, under pressure.

2. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous solution of a salt of hydrogen sulfid while maintaining said solution at a temperature of from 15 to 100 degrees centigrade; washing from the treated wood the products of decomposition effected by the action of said solution; and, drying the wood, under pressure.

3. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous solution of a salt of hydrogen sulfid; washing from the treated wood the products of decompositioneffected by the action of said solution; and,

' drying the wood, under pressure.

4. The process of'treating wood separators for storage batteries which consists in immersing them in an aqueous solution of a salt of hydrogen sulfid; removing them before the fibers and cells composing them are disintegrated and washing from the treated wood the products of decomposition ell'ected by the action of said solution; whereby said separators are deprived of a portion of their natural constituents harmful to a battery, and are rendered moreporous than natural wood, without detrimental attack upon their v 100 degrees centigrade; and washing from the treated wood the products of decomposition eifected by the action of said solution.

7. The process of treating wood separators for storage batteries which consists in Gopiea of this patent may be obtained for immersing them in an aqueous solution of sodium sulfid While maintaining said solution at a temperature of from 15' to 100 degrees centigrade; washing from the treated wood the products of decomposition effected by the action of said solution; and; drying the Wood. I

8. The process of treatin wood separators for storage batteries which consists in immersing them in an aqueous solution of a salt of hydrogen sulfid while maintaining said solution at a temperature of from 15 to 100 degrees centigrade; washing from the treated wood the products of decomposition effected by the action of said solution; and, drying the wood. i

9. The process of treating wood separators for storage batteries which consists in immersing them in an aqueous solution of a salt of hydrogen suliid; washing from the treated Wood the products of decomposition effected by the action of said solution; and, drying the wood.

10.. The process of treating sheets of wood to deprive them of lignone, without destroying the natural structure oi said sheets; which consists in subjecting them to the action of a salt of, hydrogen sulfid and. then washing them.

11. The process of treating wood separators for storage'batteries which consists in subjecting them to the action of a salt of hydrogen sulfid; and eliminating from the wood the products of the res i'ltant reaction, without destroying the natu tal structure of the wood.

12. The process of treating wood separators for storage batteries which consists in subjecting them to the action of sodiurmsultid'; and eliminating from the wood the products of the resultant reaction, without disintegrating the fibers of the Wood.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this twenty-first day of December, 1912.

JAMES M. SKINNER. Witnesses JOHN S. THoMAs, EDWARD S. PEY'IoN.

five cents each, by addressing the Commissioner of. Patents, Washington, D. 0. 

